The sacrifices that Moses offered up in order to install Aaron and his sons included ascent-offerings, sin-offerings, and peace-offerings.
Study vs. Action
וַיַּקְרֵב אֵת אֵיל הָעֹלָה וגו': (ויקרא ח:יח)
[Moses] brought forth the ascent-ram. Leviticus 8:18

The sages teach us that, in the absence of the holy Temple, someone who studies the laws of a given sacrifice is considered as if he had offered it up. But if the study of the laws of a sacrifice accomplishes the same thing as offering it up, why should we bother with the sacrifice itself, even when the Temple will be rebuilt?

The difference between the “virtual” sacrifice and the actual one is their effect on the world. While a sacrifice “offered up” by studying its laws elevates the person, it does not elevate the world around him. Only the physical sacrifice, which includes all aspects of creation – human, animal, vegetable, and mineral – elevates the world at large.

Thus, we should always seek a practical, tangible way to apply the spiritual inspiration or insight we garner, in order for it to affect and elevate not merely ourselves, but the entire world.1